Cartridge supporting magazines are known, such as for use with a number of firearms. By definition a magazine is an ammunition storage and feeding device within or attached to a repeating firearm. Magazines may be integral to the firearm (fixed) or removable (detachable and function by moving the cartridges (ammunition or bullets) stored in the magazine into a position where they may be loaded into the firearm chamber by the action (reciprocating bolt or otherwise) of the firearm. Magazines come in many shapes and sizes, from bolt action, express rifles that hold only a few rounds to semi-automatic and fully automatic machine guns that hold hundreds of rounds.
The most popular type of magazine in modern rifles and handguns, a box magazine stores cartridges in a column, either one above the other or staggered zigzag fashion. As the firearm cycles, cartridges are moved to the top of the magazine by a follower driven by spring compression to either a single feed position or side-by-side feed positions. Box magazines may be integral to the firearm or detachable.
In the latter instance, a detachable box magazine is a self-contained mechanism capable of being loaded or unloaded while detached from the host firearm and which is attached via a slot in the firearm receiver, usually below the action but occasionally to the side (Sten, FG42, Johnson LMG) or on top (Madsen machine guns, Bren gun, FN P90). When the magazine is empty, it can be detached from the firearm and replaced by another full magazine. This significantly speeds the process of reloading, allowing the operator quick access to ammunition. This type of magazine may be straight or curved, the curve being necessary if the rifle uses rimmed ammunition or ammunition with a tapered case.